Some processors, such as microprocessors, have memory arrays to store information (such as instruction and data caches). In some cases the memory arrays are volatile, as the memories are enabled to retain information only when at least some power is applied, that is, the memories lose the information without power. Retaining information in the memory arrays consumes power, even when the information is not accessed. The power consumed while retaining information arises, for example, from leakage currents associated with circuitry (such as transistors) in the memory arrays. In some memory arrays, accessing (such as reading or writing) the information consumes more power than retaining the information.
In some processors, power consumed by memory arrays is significant, leading to increased cooling costs, reduced battery life, and reduced reliability.